A Tri-Slope Gate Driving GaN DC-DC Converter With Spurious Noise Compression and Ringing Suppression for Automotive Applications

Targeting on electromagnetic interference (EMI) regulation and ringing suppression issues in automotive applications, this paper presents a gallium nitride (GaN)-based dc-dc converter operating at 10 MHz. A spurious noise compression technique compresses and re-distributes spurious switching noise within a defined frequency sideband, achieving EMI noise reduction at main switching frequency and its harmonics. Meanwhile, a tri-slope gate driver is designed to control voltage and current slew rates of GaN switches for effective ringing suppression, which is adaptive to load and input voltage changes. Tailored for high switching frequency and high-efficiency operation, the dynamic level shifters achieve about 0.8-ns propagation delay and near-zero quiescent current. Fabricated in a 0.35-μm Bipolar-CMOS-DMOS process, the converter accomplishes an EMI noise reduction of 40.5 dBμV and suppresses VSW ringing by 79.3%. The converter retains above 60% efficiency over 96.6% of its 6-W power range, with a peak efficiency of 85.5% at 1.5-W load.